Replacement cassette body for PlanetX model 'B' wheels

[Ray]

The 10speed Shimano cassette sprockets on my PX model 'B' wheels have bitten into the splines on the cassette body, resulting in some difficulty removing the cassette. PX don't seem to have stocks of replacement bodies - and, in any case, I'd prefer if possible to replace it with something harder. It seems this is a well-known problem with these wheels. Does anyone know of an alternative? Cheapish, if possible, because these are used wheels which didn't cost a lot in the first place.


btw I had tightened the cassette firmly, and I'm no gorilla - 68kg and 72yo. Never had this problem with all grades of Shimano cassettes over many years.

[Brucey]

this body
http://www.sjscycles.co.uk/ambrosio-cassette-freehub-body-for-11-speed-prod35531/

(presently out of stock) fits ambrosio and some novatec hubs. It might fit yours too? It has hardened inserts where the sprockets bear.

You may well have tightened the cassette lockring 'tight' but unless you used a torque wrench you won't know how tight that was. In addition the actual clamping force can vary wildly because of the possible variations in the serrations on the lockring.

FWIW I would normally only use a lightweight 'carrier' type cassette on an aluminium freehub body, because the low gear sprockets cannot bite into the body in the same way. These cassettes usually come with a shim washer between the lockring and the cassette, which allows the lockring to tighten more uniformly, providing a more consistent (and higher) clamping force for any given torque value.

Whatever kind of cassette you use, it is a very good idea to retorque the lockring at regular intervals, else (as you have found) any small amount of movement can go unnoticed and will only get worse as time goes on. Probably you can dress your freehub body and carry on using it. I have also seen people introduce hard shims into the interface to reduce wear, but once the body worn, it is difficult to do that in a useful fashion.

cheers

[Ray]

Thanks, that's very helpful.

this body
http://www.sjscycles.co.uk/ambrosio-cassette-freehub-body-for-11-speed-prod35531/

(presently out of stock) fits ambrosio and some novatec hubs. It might fit yours too? It has hardened inserts where the sprockets bear.

- although at £70 I doubt that it'd be worth it on a 5yo pair of £100 wheels.

may well have tightened the cassette lockring 'tight' but unless you used a torque wrench you won't know how tight that was. In addition the actual clamping force can vary wildly because of the possible variations in the serrations on the lockring.

Right. I didn't use a torque wrench but, knowing that tightness is important, I always give it some grunt - enough to feel the spokes give and the wheel flex. But OK, maybe not enough. Which prompts me to wonder whether you can really get it tight enough to avoid some slippage under load?

I would normally only use a lightweight 'carrier' type cassette on an aluminium freehub body, because the low gear sprockets cannot bite into the body in the same way. These cassettes usually come with a shim washer between the lockring and the cassette, which allows the lockring to tighten more uniformly, providing a more consistent (and higher) clamping force for any given torque value.

I used (I think?) a Shimano 105 10spd cassette. Only the 3 largest sprockets were on a carrier. Unless you are able to handle the cassette before buying (say, from the LBS) is there some way of knowing which ones have a carrier?

it is a very good idea to retorque the lockring at regular intervals, else (as you have found) any small amount of movement can go unnoticed and will only get worse as time goes on.

Thanks - will make a point of doing that.

I'll keep using the wheel for now, but may decide to bin it if/when it happens again, and replace it with something more robust.
Because the wheel set is otherwise OK, one option might be to build the rim and spokes on to another cassette hub. Might not be that simple, though, to find a straight swop - Shimano type, same hub diameter, 24 spoke holes. Again, the cost would need to be proportionate. Any thoughts?

Once again, I'm very grateful for your advice, Brucey.

[Brucey]

you can buy 24 hole freehubs but then again a cheap wheelset with a steel freehub body isn't that pricey either. You can get some cracking deals eg shimano R500 right now I think. I guess if the rims are OK it might be worth rebuilding but if they are worn then the wheelset is probably past its best anyway.

I note that (AFAIK) shimano have never produced an alloy freehub body with the standard spline on it; when they did make an aluminium freehub body, (eg for Ultegra 10s) they revised the spline too.

Regarding the cassettes with carriers; it can vary with the ratios selected even for the same model of cassette. But usually you can find the EV techdoc for the cassette model and this will show if the sprockets are on carrier(s) or not quite well.

eg cs-5600
http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCEQFjAAahUKEwiR3Mz5jMfHAhWLbRQKHWAeA_o&url=http%3A%2F%2Fsi.shimano.com%2Fphp%2Fdownload.php%3Ffile%3Dpdf%2Fev%2FEV-CS-5600-2455C.pdf&ei=QuDdVZGzMIvbUeC8jNAP&usg=AFQjCNFDvpEeS6tMW7UkM5OjDtb2sD4Uog

a final comment is that on some freehub bodies, the lockring bottoms on the freehub body instead of clamping the cassette. You can check for this by noting how far the lockring screws onto the freehub when there are no cogs present and comparing this with the final setting (use the wide spline as a reference point). If you add a shim or two in the right place you can usually get it all to work right.

cheers

[Ray]

OK, having replaced the cassette tightly (!), I'll ride it until the end of summer (today's weather makes me wonder if that's already upon us ) before considering my next move. It does look as if readily obtainable cassettes only employ carriers on the bottom few sprockets (just like the one I've been using) so I'll most probably replace the rear wheel with a standard, steel-bodied, Shimano-hubbed job. I've no real 'need for speed' so minimal spoking is not vital - 32 or maybe 28 will be fine.

For many years before I read about the importance of tightening cassette lockrings I used to just snug them up, and seem to remember that on at least one occasion I had one work quite loose. Despite this, and despite often using bottom-end Shimano hubs, I never had a real problem with damaged splines. Some marking perhaps, but nothing to worry about. Thinking about it, I also seem to recall that more of the sprockets were either on carriers, or pinned/riveted together (?). Nowadays I tend to have moved up the range (with the obvious exception of these PX wheels, which came with a complete bike), and there's no way I have become stronger! Therefore I'll be hoping and expecting not to have problems.

Cheers

[Brucey]

I have seen one or two steel freehub bodies that had worn splines but it was nothing really serious. In each case the rest of the bike was absolutely jiggered; the whole thing had clearly been to hell and back, so the wear on the freehub body splines would have been the least of your worries!

cheers

[Valbrona]

If it's a Novatec hub: http://bdopcycling.com/Wheel%20Parts.asp

[Ray]

Thanks, Valbrona. I have heard that PX may use re-branded Novatec hubs, but I can't be certain that the replacement bodies will fit. If so, however, it's quite likely they'd be just as soft. Also, those prices hardly make it worthwhile.

Anyway, I've probably done approaching 10,000 miles on those wheels, so I don't feel too hard done by!